Sheet feeding apparatus

ABSTRACT

A sheet feeding apparatus, including a sheet loading portion on which a plurality of sheets are loaded, a sheet take-in portion to take in the sheet loaded on the sheet loading portion, a first mechanism to displace between a first sheet and a second sheet in the sheets which are taken in from the sheet take-in portion and are overlapping up and down, and a second mechanism to sandwich and convey the first sheet displaced by the first mechanism to a following process.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2009-56549, filed on Mar. 10, 2009; the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a sheet feeding apparatus to take in a sheet one by one out of sheets loaded on a loading portion such as a hopper table and so on into an inside of a sheet processing apparatus such as an optical character reader and so on.

2. Description of the Background

A sheet fed type optical character reader is known which takes in a sheet loaded on a hopper table into an inside of the apparatus by a sheet feeding portion and to read in characters and figures and so on recorded on the sheet by the optical reading portion as an image.

In a sheet feeding portion of a conventional sheet fed type optical character reader, a separating portion composed of rollers and belts is usually provided by only one stage. In case of taking in the sheet from a hopper table, the one stage separating portion takes in the sheets and, while separating the sheets one by one, sends the sheet to a conveying route. (Refer to Patent Document 1, for example)

Patent Document 1: Japan Patent Disclosure (Kokai) P2006-151636

In the above-described prior art, a separating portion composed of rollers and belts can not surely separate the sheets one by one by itself As a result, a double feeding takes place that a plurality of the sheets are sent to a following processing portion in the overlapping state. Accordingly, there was a problem that a sheet from which the reading processing is not performed or a trouble such as a jam takes place by a cause of double feeding the sheets.

SUMMARY OF THE INVENTION

The present invention is made to solve the above-described problem, and an object of the present invention is to provide a sheet feeding apparatus which can surely separate the sheet one by one from a sheet loading portion on which the sheets are loaded and convey the separated sheet.

According to an aspect of the present invention, there is provided a sheet feeding apparatus, including a sheet loading portion on which a plurality of sheets are loaded, a sheet take-in portion to take in the sheet loaded on the sheet loading portion, a first mechanism to displace between a first sheet and a second sheet in the sheets which are taken in from the sheet take-in portion and are overlapping up and down and a second mechanism to sandwich and convey the first sheet displaced by the first mechanism to a following process.

According to another aspect of the present invention, there is provided a sheet feeding apparatus, including a sheet loading portion on which a plurality of sheets are loaded, a sheet take-in portion with a roller provided above the sheet loading portion to take in the sheet into the apparatus by a friction force of the roller contacting a surface of the sheet loaded on the sheet loading portion by rotating the roller in a first direction, a belt with a slope portion to contact a lower side second sheet in case that a first sheet and the second sheet are taken in from the sheet take-in portion and are overlapping up and down, to displace the first sheet from the second sheet by rotating in a second direction which is an adverse direction of the first direction to take in the sheet, and a conveying mechanism to convey the displaced first sheet.

According to the present invention, a sheet feeding apparatus can surely separate a sheet from sheets loaded on a loading portion and covey the separated sheet.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

FIG. 1 is an appearance diagram showing an optical character reader according to an embodiment of the present invention;

FIG. 2 is a side view showing schematically a construction of the optical character reader shown in FIG. 1;

FIG. 3 is a block diagram showing functionally a construction of a control system in the optical character reader shown in FIG. 1;

FIG. 4 is a view showing precisely a construction of a sheet feeding portion of the optical character reader;

FIG. 5 is a view showing a state of the sheet feeding portion when taking in the sheets is started;

FIG. 6 is a view showing a modification of the present invention; and

FIG. 7 is a view showing an operation of the modification.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, the embodiments of the present invention will be described below.

FIG. 1 is an appearance diagram showing an optical character reader according to a first embodiment of the present invention, FIG. 2 is a side view showing schematically a construction of the optical character reader, FIG. 3 is a block diagram showing functionally a construction of a control system in the optical character reader, and FIG. 4 is a enlarged view showing a sheet feeding portion.

In an optical character reader shown in FIG. 1, a sheet take-in port and a sheet discharge port are provided at a front portion of a chassis 1. The optical character reader takes in a sheet from the sheet take-in port into an inside of the apparatus, while conveying the sheet along a conveying route, reads in characters and figures and so on recorded on the sheet as an image data, and then discharges the sheet from the sheet discharge port.

At the front portion of the chassis 1, a display 47 as a display unit and an operating unit 48 are provided. On the display 47, various menus such as operating procedures, processing state and error contents and so on are displayed. On the operating unit 48, operating buttons are provided so as to instruct to start or stop processing the sheets and to release errors.

As shown in FIG. 2 through FIG. 4, the optical character reader is provided with a hopper table 2 (hereinafter, referred to as “hopper 2”) as a sheet loading portion provided extending from the front of the chassis 1, a sheet feeding portion 11 provided in the vicinity of the sheet take-in port of the chassis 1, an optical reading portion 14 provided at a down stream side of a conveying direction of the sheet feeding portion 11, a print head 15 of a wire dot matrix type provided at a down stream side of the conveying direction, an ink ribbon cartridge 20, a sheet sorting portion such as a flapper 17, an accept stacker 18 and a reject stacker 19 and so on, a power source portion 20 to supply power, and a controller 40.

As shown in FIG. 3, the controller 40 is provided with a CPU 41, a memory 42 and an interface 43. The CPU 41, the memory 42 and the interface 43 are connected via buses, respectively. The optical reading portion 14, the flapper 17, the display 47, the operating unit 48, a driving portion 44 to drive a motor and so on, a sheet thickness detecting portion 10 provided at the conveying route, and the print head 15 are connected to the interface 43.

The hopper 2 loads the sheets which are objects to be conveyed in stacked state, and is provided at the sheet take-in port of the chassis 1 so as to move up and down freely. On the hopper 2, sheets P are loaded at the state that many sheets are stacked.

Regarding the sheet, in case of the description where the double feeding of the sheets is not taken into consideration, the sheets are indicated simply as sheets P. And in case of the description where the double feeding of the sheets is taken into consideration, the sheets are indicated as a sheet P1, a sheet P2 and so on.

The sheet feeding portion 11 is provided with a pickup roller 3 as a sheet take-in portion, a separating portion 60 having feed rollers 4, a first belt 5, separate rollers 7 a˜7 d and a second belt 6, and the sheet thickness detecting portion 10 composed of a pinch roller 8 a, a drive roller 8 b and a displacement sensor 9 arranged above the pinch roller 8 a.

The pickup roller 3 is arranged above the hopper 2. The pickup roller 3 is arranged such that the lower surface of the pickup roller 3 coincides approximately with a reference conveying position T. The pickup roller 3 contacts an uppermost sheet P1 out of a plurality of the sheets P loaded on the risen hopper 2. And the pickup roller 3 takes in the uppermost sheet P1 from the sheet take-in port into the inside of the apparatus by the friction force at the surface of the pickup roller 3, by rotating in the direction of an arrow B, that is, in the clockwise direction

In the separating portion 60, the two feed rollers 4 are provided. The first belt 5 is belted around the two feed rollers 4. When the two feed rollers 4 rotate in the direction of the arrow B, the first belt 5 rotates in the direction of the arrow B. The first belt 5 has a function to convey the sheet P1 in the direction of an arrow E based on the friction force generated between the sheet P1 and the first belt 5 by contacting the sheet P1 taken in by the pick up roller 3.

On the other hand, the four separate rollers 7 a, 7 b, 7 c, 7 d are provided below the feed rollers 4. The second belt 6 is belted around the four separate rollers 7 a, 7 b, 7 c, 7 d. The separate roller 7 c is attached to a driving axis via a torque limiter. The separate rollers 7 a, 7 b, 7 d are attached to axes so as to rotate freely, respectively. The separate roller 7 c rotates based on the torque acted on from the driving axis in case that the torque acted on to the separate roller 7 c from the outside is not more than a cutoff torque set in the torque limiter. On the other hand, the separate roller 7 c rotates based on the torque acted on from the outside regardless of the torque acted on from the driving axis in case that the torque acted on to the separate roller 7 c from the outside is not less than the cutoff torque set in the torque limiter. When the separate roller 7 c rotates in the direction of an arrow A according to the rotation of the driving axis, the second belt 6 rotates in the direction of the arrow A. The second belt 6 conveys the sheet P2 which contacts the second belt 6 in an adverse direction of the arrow E based on the friction force generated between the second belt 6 and the sheet P2.

In FIG. 4 and FIG. 5, though it is shown that there is a gap between the first belt 5 and the second belt 6, the first belt 5 and the second belt 6 are actually in the contacting state.

When the pickup roller 3 rotates in the direction of the arrow B and feeds the uppermost sheet P1 on the hopper 2 in the direction of the arrow C, in case that the uppermost sheet P1 and the next sheet P2 are fed concurrently, that is, double fed, the tip portion of the fed sheet P2 contacts a slope portion 6 a of the second belt 6.

Then the sheet P1 is continued to be fed in the direction of the arrow C by the pickup roller 3. On the other hand, as the sheet P2 contacts the second belt 6, a friction force generates between the sheet P2 and the second belt 6. For the reason, the sheet P2 receives a sheet feeding force in the adverse direction of the arrow C by the rotation of the second belt 6 in the direction of the arrow A. In this time, as the sheet feeding force in the adverse direction of the arrow C given to the sheet P2 by the second belt 6 is larger than the friction force between the sheet P1 and the sheet P2, the sheet P2 is fed in the adverse direction of the arrow C by the second belt 6. For the reason, a displacement is generated between the sheet P1 and the sheet P2, and only the sheet P1 is fed in the direction of the arrow C.

Then, the tip portion of the sheet P1 contacts the first belt 5, and the sheet P1 is continued to be fed in the direction of the arrow C. When the sheet P1 is fed in the direction of the arrow C by the first belt 5, the separate roller 7 c receives the torque in the adverse direction of the arrow A from the first belt 5 via the second belt 6. A value of the torque in the adverse direction of the arrow A received by the separate roller 7 c is not less than a value of the cutoff torque of the torque limiter. Thus, the transmission of the torque from the driving axis to the separate roller 7 c is cut off by the action of the torque limiter. For the reason, the separate roller 7 c rotates in the adverse direction of the arrow A by the torque received from the first belt 5 via the second belt 6. As a result, the sheet P1 is fed in the direction of the arrow C in the state that the sheet P1 is sandwiched between the first belt 5 and the second belt 6.

The pinch roller 8 a and the drive roller 8 b of the sheet thickness detecting portion 10 are arranged so as to face each other and to sandwich the reference conveying position T above and below. The drive roller 8 b is provided so as to rotate by the axis. The pinch roller 8 a is provided so as to rotate freely around the axis and contacts the drive roller 8 b. The drive roller 8 b along with the pinch roller 8 a sandwiches the sheet P, draws in the sheet P, and conveys the sheet P to the downstream. The pinch roller 8 a is provided so as to move up and down in accordance with the thickness of the sheet P, when the pinch roller 8 a and the drive roller 8 b convey the sheet P. The displacement sensor 9 detects a moving amount when the pinch roller 8 a moves up and down, that is a displacement amount.

The displacement sensor 9 is a detecting means to detect the double feeding of the sheet. The displacement sensor 9 sends a position detecting signal indicating the displacement amount to the controller 40. The CPU 41 receives the position detecting signal from the displacement sensor 9, compares the displacement amount with a reference paper thickness of one sheet set previously in the memory 42, and judges the double feeding of the sheet. The reference paper thickness has a range such as 0.09 mm±0.02 mm, for example.

Other the pinch rollers 13 and the drive rollers 12 provided subsequent to the optical reading portion 14 are arranged facing each other at the points inside the apparatus so as to form the conveying route of the sheet P as shown in FIG. 2.

The memory 42 stores a control program. The CPU controls the optical character reader by reading out the control program from the memory 42 and executing the control program. Beside this, the memory 42 is used to store the image which is read in by the optical reading portion 14.

The CPU 41 control motors which are driving sources to drive the pickup roller 3, the feed rollers 4, the separate roller 7 c, the drive roller 8 b and the drive rollers 12 via the driving portion 44.

For example, when a start operation is performed to read in the sheet P from the operating unit 48, and the CPU 41 accepts the instruction, the CPU 41 raises the hopper 2 by controlling a motor (not shown) for moving the hopper 48 up and down. In addition, along with the action, the CPU 41 rotates the pickup roller 3 in the direction of the arrow B by controlling the motor (not shown) to rotate the driving axis of the pickup roller 3.

The optical reading portion 14 is provided on the conveying route at the down stream of the sheet feeding portion 11. The optical reading potion 14 is an image reading unit to read in the image from the sheet P on the conveying route. The optical reading portion 14 is composed of a light source lamp 30 to irradiate light to the sheet P, mirrors 31, 32, a lens 33 and a CCD line image sensor 34.

The print head 15 is provided at the down stream conveying route at a position near the sheet discharge port. The print head 15 is provided to face a platen roller 16. The print head 15 along with the platen roller 16 arranged to face the print head 15 are referred to as a printing portion. The print head 15 prints a reference number and a mark and so on indicating that the sheet P has been processed on the sheet P from which the information is normally read in by the optical reading portion 14.

The flapper 17 is provided at the down stream side in the conveying direction from the print head 15 (in front of the sheet discharge port). The flapper 17 is drive controlled by the CPU 41 and sorts the sheet P in the direction of the accept stacker 18 or the reject stacker 19.

The accept stacker 18 is a sheet stacking portion to stack the sheet P from which the reading processing is performed normally. The reject stacker 19 is a sheet stacking portion to stack the sheet P from which the reading processing is not performed normally.

Hereinafter, an operation of the optical character reader will be described with reference to FIG. 5.

In the optical character reader, when an instruction command to start processing is inputted from the operating unit 48, the controller 40 rotates the pickup roller 3 in the direction of the arrow B so as to raise the hopper 2 by controlling the driving portion 44.

Then, when a sensor (not shown) detects that the uppermost sheet P1 out of the sheets P loaded on the hopper 2 contacts the pickup roller 3 at the reference conveying position T, the controller 40 stops the hopper 2 to be raised. At this time, the uppermost sheet P1 is taken into the conveying route by the rotating pickup roller 3.

The controller 40 controls the driving portion 44 such that the feed rollers 4 are rotated in the direction of the arrow B and the separate roller 7 c is rotated in the direction of the arrow A.

Here, it is assumed that the double feeding of the sheets takes place and the uppermost sheet P1 and the lower sheet P2 are taken into the apparatus in the overlapping state.

In this case, the sheet P2 contacts the slope portion 6 a of the first belt 6 rotating in the direction of the arrow A, a displacement arises between the sheet P1 and the sheet P2. As a result, only the sheet P1 is fed in the direction of the arrow C in the state that the sheet P1 is sandwiched between the first belt 5 and the second belt 6.

At the sheet thickness detecting portion 10, when the sheet P1 passes between the drive roller 8 b and the pinch roller 8 a, the pinch roller 8 a is hoisted by the sheet thickness of the sheet P1 so that the height of the pinch roller 8 a displaces. The displacement sensor 9 detects the displacement amount of the height and sends a position detecting signal indicating the displacement amount to the controller 40.

The controller 40 compares the displacement amount with a preliminarily set reference thickness of a sheet and judges whether or not the thickness of the sheet P1 is normal.

As a result of the judgment, in case that the thickness of the sheet P is not normal, the CPU 41 controls so that a buzzer, or the display 47 and so on generates an alarm (warning tone or warning display), and stops the operation of the apparatus.

An electrical signal of the image which is read out by the optical reading portion 14 is outputted to the controller 40. The CPU 41 forms an image of the surface of the sheet from the inputted electrical signal, and executes a post processing for the image. Regarding the post processing, there is character recognition processing and so on. The sheet P from which the reading processing at the surface is executed by the optical reading portion 14 and the controller 40 as described above is conveyed to the print head 15 side on the conveying route.

When the character recognition processing is finished normally, the CPU 41 executes the print processing by the print head 15 on the sheet P which reached the position of the print head 15.

The CPU 41 controls the print head 15 so that the reference number indicating that the conveyed sheet P was reading processed, for example, is printed on the sheet by the printing portion. Then, the CPU 41 drives the flapper 17 to switch over the conveying direction for the accept stacker 18 side, sorts the printed sheet P, and stacks the sheet P on the accept stacker 18.

On the other hand, after reading the above-described Image, when the character recognition processing is not finished normally, the CPU 41 drives the flapper 17 to switch over the conveying direction for the reject stacker 19 side without printing and stacks the sheet P on the reject stacker 19.

These operations are repeated, and when the sheet P does not remain in the hopper 2 or a command indicating to stop (a stop instruction) is inputted, the CPU stops the reading operation of the sheet P.

As described above, according to the optical character reader according to the embodiment, a slope portion 6 a is formed on the second belt 6 which rotates in the reverse direction of the rotation direction of the first belt 5. By this, when the sheets P1 and P2 are double fed, a displacement takes place between the sheet P1 and the lower sheet P2 which contacts the slope portion 6 a of the second belt 6, and thus only the sheet P1 is fed in the direction of the arrow C.

Hereinbefore, the embodiment of the present invention is described taking an optical character reader for example, but the present invention is not limited to these embodiments. The present invention can be applied to any apparatus provided with a sheet feeding apparatus where it is required to convey sheets without double feeding. In addition, the present invention can be changed variously within the range without departing the gist of the invention.

Hereinafter, a modification of the above-described embodiments is described with reference to FIG. 6 and FIG. 7. Here, the same reference numerals are given to the same components in the above-described embodiments, and the description thereof is omitted.

As shown in FIG. 6, a modification is an example in case of being provided with a sheet loading portion 2 a to load the sheets P with a slope and a roller 61.

In this case, as the sheet take-in port is provided in the obliquely downward direction of the sheet loading portion 2 a, the sheet P is taken-in in the obliquely downward direction. The roller 61 is provided at the lower side of the sheet take-in port facing the pickup roller 3, and functions as a guide mechanism to lead the sheet P to the slope portion 6 a provided in the rising direction of the belt 6.

In the modification, when the pickup roller 3 rotates in the direction of the arrow B, the sheet P is taken in from the sheet loading portion 2 a in the oblique downward direction.

Then, the roller 61 arranged under the pickup roller 3 leads the sheet P to the slope portion 6 a as shown in FIG. 7. Thus, in case that a plurality of sheets P1, P2 are double fed, the lower side sheet P2 contacts the slope portion 6 a in the same manner as in the case of FIG. 5, and the lower side sheet P2 is fed in the adverse direction of the arrow C by the second belt 6.

For the reason, a displacement takes place between the sheet P1 and the sheet P2, and only the sheet P1 is fed in the direction of the arrow C.

Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein. 

1. A sheet feeding apparatus, comprising: a sheet loading portion on which a plurality of sheets are loaded; a sheet take-in portion to take in the sheet loaded on the sheet loading portion; a first mechanism to displace between a first sheet and a second sheet in the sheets which are taken in from the sheet take-in portion and are overlapping up and down; and a second mechanism to sandwich and convey the first sheet displaced by the first mechanism to a following process.
 2. A sheet feeding apparatus, comprising: a sheet loading portion on which a plurality of sheets are loaded; a sheet take-in portion with a roller provided above the sheet loading portion to take in the sheet into the apparatus by a friction force of the roller contacting a surface of the sheet loaded on the sheet loading portion by rotating the roller in a first direction; a belt with a slope portion to contact a lower side second sheet in case that a first sheet and the second sheet are taken in from the sheet take-in portion and are overlapping up and down, to displace the first sheet from the second sheet by rotating in a second direction which is an adverse direction of the first direction to take in the sheet; and a conveying mechanism to convey the displaced first sheet.
 3. The sheet feeding apparatus as recited in claim 2, wherein: the sheet loading portion loads a plurality of the sheets with a slope. 